Electro Power for small aircraft and drones

[Ivan]

Hello Aleatorylamp,

I am NOT LOOKING FOR EXCUSES TO "SCREW" with the Air File. YOU WANTED a 350 Hp engine at S.L. again, so now you tell me HOW THE HECK ELSE am I to get this bugger down to that power again WITHOUT "SCREWING" with the Torque and Friction Graphs ???

HOW do you expect to get 350 Hp from an engine that has Torque and Friction Graphs set already for 402 Hp at 500 ft??? I would think that the whole point of having these graphs is to set required HP.

What I expected is that you archived prior versions of Air files, especially ones with notable changes. The first known good version would have been worthy of archiving. You should not have to work your way back to some place you have already been before.
The A6M2 Air file I was working on last night is version 0.55 and there are notes in each version describing the changes that were done for the version number change. This project dates back well over 11 years.

If you are so sensitive about the Torque and Friction Graphs, YOU tell me what values YOU WANT to have in them. There are only a few columns in each graph anyway, so it won´t put you out too much.

If I had to pick something, it would have been whatever the numbers were for the initial 350 HP version. I still have the one I derived from the P-40N because I believe so far it is the only really good version I have actually worked on.

Then you added: "When I asked you earlier why you were using Water Methanol Injection, the correct answer was: Because the manifold pressure was getting into the range in which the engine might experience detonations without ANTI DETONANT INJECTION."

NO, that was not the reason! AS I ALREADY SAID, all I wanted was to separate 5-minute Take-off power into F10 to prevent abuse of full power, and WEP Type 2 is the only option that won´t destroy the whole engine - it only destroys the supercharger if abused.
However, I am currently NOT using WEP type 2 any longer for these exercises anyway.

BTW: Can you hear the detonations in CFS???

The question was phrased incorrectly. It should have been, "Why do you think Jon Sharp used Water Methanol Injection?"
There is nothing in these SIMULATORS that enforce the physical realities of actual engines. You can bump the Manifold Pressure up to 65 inches and never have a problem. It is OUR job to figure out what should happen and make that happen in the simulator.
That does not mean just tweaking Air file parameters because we know how to.

Then you said "I am not really interested in what numbers you are getting with 40.7 inches MP because I don't think how you got there actually makes sense. " So WHY did you say it is MY guess regarding what max. MP to put in for a 401 Hp at S.L. engine? I mentioned that I had tried higher values than 40.7 that proved to be excessive for the performance we expected. Take into account that you had already said 39.5 Hg was insufficient.

I was hoping you would realize that 44 inches as seen in the TCDS was probably too little manifold pressure to get the performance level you were trying for. That is what THIS exercise was meant to illustrate.
If a TYPE CERTIFIED engine (garden variety off the shelf type) can reach this level of manifold pressure then one has to assume that the custom Thunderbolt engines are going MUCH HIGHER to achieve the levels of power worthy of the extra cost.
Do you think Lycoming just tweaks a couple graphs to get the power level they want for their custom products?

You already know that for some of the record runs, ADI was needed. ADI is needed IN REAL LIFE to keep the engine from blowing itself up when the manifold pressure gets high enough for pre-ignition / detonation. NO, the simulator won't create a detonation condition for you. You have to be smart enough to figure out when that is likely to happen and design your virtual aeroplane accordingly.
So how do you figure this out? By using other similarly configured engines (air cooled with a single stage supercharger and without an intercooler) as examples.

None of these ideas are all that strange. It is how we learn more from working at this hobby. If all you do is tweak Air files without trying to understand why you are doing things, you won't really learn.

- Ivan.

 

[aleatorylamp]

Ivan,

Oh? So it IS the Torque and Friction Graphs after all, that have to be set differently for 400 Hp or for 350 Hp at S.L.

I write down the necessary values every time I do an altitude vs power/speed test to record the results, and it takes me 15 seconds to change the Torque and Friction graphs to go from 400 Hp at S.L. back to 350 Hp, or vice versa, and that doesn´t mean I´m always screwing or messing with graphs and the air file as you so deprecatingly comment.

Regarding ADI, I repeat, for the umpteenth time: The model I am working on doesn´t do ADI, so that´s one item less to worry about and doesn´t apply here. We are not talking about Jon Sharp´s plane - it is a Dan Wright build, and that one had no ADI, and it didn´t blow itself up, meaning it wasn´t using exorbitant supercharger values but more normal ones, as shown in the first part of the exercise for S.L. max. MP:
MP 43.5 hg: 402 hp, 382.5 mph, 40.2 prop
MP 44.0 hg: 409 hp, 394.4 mph, 40.3 prop

...and of course, we now also know it wasn´t using the standard off-the-shelf 39.5 Hg value for 350 Hp at S.L. so that one is discarded.

We know it wasn´t a 450 Hp machine, so following values would not apply:
MP 47.0 hg: 448 hp, 395.2 mph, 41.1 prop
MP 47.5 hg: 454 hp, 395.4 mph, 41.2 prop

...much less 51 Hg or 65 Hg.

Why is every morsel of useful information you provide preceded by endless numbers of confusing, ambiguous beating-around-the-bush maneuvers and misleading comments, expressed in a despective, unpleasant tone that is becoming a habit in nine out of ten messages?
I don´t see the point behind such an attitude. It´s not even annoying any longer, it´s becoming quite boring, I´m sorry to say, and I don´t know how long I will be able to continue with this.

Aleatorylamp

 

[Ivan]

Hello Aleatorylamp,

Oh? So it IS the Torque and Friction Graphs after all, that have to be set differently for 400 Hp or for 350 Hp at S.L.

Where the heck did you get THIS idea from? If this is what you THINK I said, you are mistaken and have totally missed the point of this exercise.

I write down the necessary values every time I do an altitude vs power/speed test to record the results, and it takes me 15 seconds to change the Torque and Friction graphs to go from 400 Hp at S.L. back to 350 Hp, or vice versa, and that doesn´t mean I´m always screwing or messing with graphs and the air file as you so deprecatingly comment.

So what exactly does this statement above mean???? Please read what you wrote and see if it makes any sense.
If it is related to the exercise I just suggested, then you are doing it wrong. This exercise DID NOT involve messing with Torque or Friction graphs. If your response is not related to the exercise, then I have no idea what it is about and how it is related to what we were just discussing.

This discussion is much worse than boring. There is a lot that you should already know from having worked on flight sims for so long. The way you are responding is either a willful misunderstanding or lack or comprehension of the subject matter.

- Ivan.

 

[aleatorylamp]

Oh stop it, Ivan!
Or better, go away, and leave me alone.
I should never have fallen into the trap answering your message at the beginning of this thread.
Aleatorylamp.

 

[aleatorylamp]